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Re: the Gravity of Python 2

From Roy Smith <roy@panix.com>
Newsgroups comp.lang.python
Subject Re: the Gravity of Python 2
Date 2014-01-09 09:14 -0500
Organization PANIX Public Access Internet and UNIX, NYC
Message-ID <roy-5C5BD9.09142209012014@news.panix.com> (permalink)
References (15 earlier) <CAPTjJmpoEmgF0AXo5+_sG=+uVJ6rbjsFOyCw6Cyh-3gkmDgefQ@mail.gmail.com> <52CE3416.9090501@stoneleaf.us> <CAPTjJmp6OfeMAZwbjAhT+N7dm_q3sj01cuCK9Vp7RFSf8bKnWQ@mail.gmail.com> <7wiottej72.fsf@benfinney.id.au> <mailman.5244.1389254198.18130.python-list@python.org>

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In article <mailman.5244.1389254198.18130.python-list@python.org>,
 Chris Angelico <rosuav@gmail.com> wrote:

> What can you (Roy), with your use-case, achieve with datetime that 
> you can't achieve (at least reasonably easily) with a timestamp?

As I'm mentioned several times, when you print a datetime, you get 
something that's human friendly.  When you print a timestamp (i.e. a 
float), you get a lot of digits.  I don't know about you, but I can't 
look at 1389274842 and get any feel for whether that was in the middle 
of the night or at 5 in the afternoon, near our peak traffic time.  Nor 
can I tell if it was today, yesterday, last month, or a week from next 
Tuesday.

Datetimes make it easy to do things like, "find the time of the 
preceding (or following) midnight".  Or, "what month is this timestamp 
part of?"  These are operations we need to do a lot, to answer questions 
like, "How many unique users did we have on a given day?", or "Which 
monthly database archive file do I need to grab to get information about 
this historical event?"

Datetimes are self-documenting.  If I'm in the python shell and have 
something called t, I can do help(t) or dir(t) to find out what 
operations it has.

Datetimes are self-describing.  If I have a datetime or a timedelta, I 
know what I've got.  I've written more than one bug where I assumed a 
number somebody handed me was in seconds but it turned out to be in ms.  
That can never happen with a timedelta.  We do a lot of stuff in 
javascript, where times are ms, so this is a common problem for us.

Oh, and another thing I can do with a datetime that I can't do with a 
unix timestamp.  I can represent the day I was born.

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Thread

Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-07 11:19 +1100
  Re: the Gravity of Python 2 Martijn Faassen <faassen@startifact.com> - 2014-01-07 13:54 +0100
    Re: the Gravity of Python 2 Martijn Faassen <faassen@startifact.com> - 2014-01-07 17:07 +0100
      Re: the Gravity of Python 2 Martijn Faassen <faassen@startifact.com> - 2014-01-07 17:42 +0100
        Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-08 04:00 +1100
          Re: the Gravity of Python 2 Martijn Faassen <faassen@startifact.com> - 2014-01-08 13:36 +0100
            Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-08 23:46 +1100
              Re: the Gravity of Python 2 Martijn Faassen <faassen@startifact.com> - 2014-01-08 16:08 +0100
            Re: the Gravity of Python 2 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-01-09 00:01 +1100
              Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-08 14:08 +0000
              Re: the Gravity of Python 2 Martijn Faassen <faassen@startifact.com> - 2014-01-08 16:22 +0100
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 02:39 +1100
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-08 15:50 +0000
                Re: the Gravity of Python 2 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-01-09 08:55 +1100
            Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-08 09:15 -0500
              Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-08 14:30 +0000
                Re: the Gravity of Python 2 Martijn Faassen <faassen@startifact.com> - 2014-01-08 16:26 +0100
                Re: the Gravity of Python 2 Kevin Walzer <kw@codebykevin.com> - 2014-01-08 18:42 -0500
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-08 20:27 -0500
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 12:47 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-08 21:25 -0500
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 14:17 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-08 22:35 -0500
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 15:03 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-08 23:29 -0500
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 15:34 +1100
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 15:38 +1100
                Re: the Gravity of Python 2 Ethan Furman <ethan@stoneleaf.us> - 2014-01-08 21:31 -0800
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 17:34 +1100
                Re: the Gravity of Python 2 Ben Finney <ben+python@benfinney.id.au> - 2014-01-09 17:57 +1100
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 18:56 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-09 09:14 -0500
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-10 01:57 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-09 08:21 -0800
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 16:30 +0000
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-09 09:07 -0800
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 18:20 +0000
                Re: the Gravity of Python 2 Ethan Furman <ethan@stoneleaf.us> - 2014-01-09 10:29 -0800
                Re: the Gravity of Python 2 Tim Golden <mail@timgolden.me.uk> - 2014-01-09 16:41 +0000
                RE: the Gravity of Python 2 Nick Cash <nick.cash@npcinternational.com> - 2014-01-09 16:42 +0000
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 16:50 +0000
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-10 07:35 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-09 12:54 -0800
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-10 08:12 +1100
                Re: the Gravity of Python 2 Dan Sommers <dan@tombstonezero.net> - 2014-01-09 15:01 +0000
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-10 02:17 +1100
                Re: the Gravity of Python 2 Ethan Furman <ethan@stoneleaf.us> - 2014-01-09 07:56 -0800
                Re: the Gravity of Python 2 Kushal Kumaran <kushal.kumaran@gmail.com> - 2014-01-09 11:36 +0530
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 08:53 +0000
                Re: the Gravity of Python 2 Ben Finney <ben+python@benfinney.id.au> - 2014-01-09 20:03 +1100
                Re: the Gravity of Python 2 Kushal Kumaran <kushal.kumaran@gmail.com> - 2014-01-09 14:51 +0530
                Re: the Gravity of Python 2 Piet van Oostrum <piet@vanoostrum.org> - 2014-01-09 12:26 +0100
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 09:51 +0000
                Re: the Gravity of Python 2 Ben Finney <ben+python@benfinney.id.au> - 2014-01-10 00:35 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-09 09:32 -0500
                Re: the Gravity of Python 2 Ben Finney <ben+python@benfinney.id.au> - 2014-01-09 14:34 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-08 22:44 -0500
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 14:42 +1100
                Re: the Gravity of Python 2 Piet van Oostrum <piet@vanoostrum.org> - 2014-01-09 15:06 +0100
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-10 01:34 +1100
                Re: the Gravity of Python 2 Roy Smith <roy@panix.com> - 2014-01-09 09:44 -0500
                Re: the Gravity of Python 2 Piet van Oostrum <piet@vanoostrum.org> - 2014-01-09 17:51 +0100
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-10 07:43 +1100
                Time zones and why they change so damned often (was: the Gravity of Python 2) Ben Finney <ben+python@benfinney.id.au> - 2014-01-09 14:54 +1100
                Re: Time zones and why they change so damned often (was: the Gravity of Python 2) Chris Angelico <rosuav@gmail.com> - 2014-01-09 15:14 +1100
                Re: Time zones and why they change so damned often (was: the Gravity of Python 2) Peter Pearson <ppearson@nowhere.invalid> - 2014-01-10 18:22 +0000
                Re: Time zones and why they change so damned often MRAB <python@mrabarnett.plus.com> - 2014-01-10 18:48 +0000
                Re: Time zones and why they change so damned often Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-10 18:53 +0000
                Re: Time zones and why they change so damned often Grant Edwards <invalid@invalid.invalid> - 2014-01-10 19:55 +0000
                Re: Time zones and why they change so damned often Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-01-10 19:45 -0500
                Re: Time zones and why they change so damned often Gene Heskett <gheskett@wdtv.com> - 2014-01-10 21:53 -0500
                Re: Time zones and why they change so damned often (was: the Gravity of Python 2) Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-01-10 19:43 -0500
                Re: Time zones and why they change so damned often (was: the Gravity of Python 2) Roy Smith <roy@panix.com> - 2014-01-10 19:49 -0500
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 07:10 +0000
                Re: Time zones and why they change so damned often Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 07:17 +0000
                Re: Time zones and why they change so damned often Alister <alister.ware@ntlworld.com> - 2014-01-09 12:07 +0000
                Re: Time zones and why they change so damned often Bob Martin <bob.martin@excite.com> - 2014-01-10 07:31 +0000
                Re: Time zones and why they change so damned often Alister <alister.ware@ntlworld.com> - 2014-01-10 09:04 +0000
                Re: Time zones and why they change so damned often Bob Martin <bob.martin@excite.com> - 2014-01-11 07:52 +0000
                Re: Time zones and why they change so damned often Alister <alister.ware@ntlworld.com> - 2014-01-11 11:10 +0000
                Re: Time zones and why they change so damned often Alister <alister.ware@ntlworld.com> - 2014-01-11 11:14 +0000
                Re: Time zones and why they change so damned often Alister <alister.ware@ntlworld.com> - 2014-01-11 11:14 +0000
                Re: Time zones and why they change so damned often (was: the Gravity
 of Python 2) Dave Angel <davea@davea.name> - 2014-01-09 10:34 -0500
                Re: the Gravity of Python 2 Ethan Furman <ethan@stoneleaf.us> - 2014-01-08 17:52 -0800
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 13:09 +1100
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 08:42 +0000
                Re: the Gravity of Python 2 Ethan Furman <ethan@stoneleaf.us> - 2014-01-09 08:01 -0800
                Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-09 18:18 +0000
                Re: the Gravity of Python 2 Ethan Furman <ethan@stoneleaf.us> - 2014-01-09 10:33 -0800
              Re: the Gravity of Python 2 Pedro Larroy <pedro.larroy.lists@gmail.com> - 2014-01-08 15:45 +0100
              Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 01:50 +1100
                Re: the Gravity of Python 2 Grant Edwards <invalid@invalid.invalid> - 2014-01-08 15:06 +0000
                Re: the Gravity of Python 2 Chris Angelico <rosuav@gmail.com> - 2014-01-09 02:31 +1100
              Re: the Gravity of Python 2 Terry Reedy <tjreedy@udel.edu> - 2014-01-08 15:45 -0500
            Re: the Gravity of Python 2 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-08 14:15 +0000

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